Dental restorative compositions comprising a polymerizable resinous composition plus a filler are finding wide acceptance in the practice of dentistry. An illustration of such compositions is the dental filling material described by Lee et al. in U.S. Pat. No. 3,539,533. However, such resin based dental filling materials have found limited use for the filling of cavities on the grinding surfaces of molars. The reason for this is that such compositions have been found to have inadequate wearing properties to withstand the stresses which are normal in such areas. Among the factors that contribute to the inadequate wear properties of the prior art resinous dental restorative dental compositions are microfractures of the overall composite and debonding that occurs at the filler/polymer matrix interface. Both of these are most likely to occur during the cyclic loads encountered while chewing in an aqueous environment, with modest temperature fluctuations. Inadequate hydrolytic stability appears to contribute to both the microfractures and debonding. The present invention is directed to a dental restorative composition that substantially improves hydrolytic stability, resistance to debonding at the filler/polymer interface, and resistance to the formation and propagation of microfractures in the composite.